Progress in the treatment of acute myocardial infarction (AMI)， chronic coronary artery disease and their immediate complications has led to an increasing number of surviving patients with residual left ventricular dysfunction. It has been shown that viable myocardium in post-AMI patients and chronic heart failure patients plays an important role in predicting their prognosis and making clinical decisions. Viable myocardium refers to myocardium with reversible contractile dysfunction that occurs in coronary ischemia or after ischemia-reperfusion, but still has contractile reserve. Myocardial microvascular integrity is in correspondence with myocardial viability. Myocardial contrast echocardiography can evaluate the microvascular integrity of myocardial dysfunctional areas in patients with AMI or chronic coronary artery disease, detect viable myocardium， predict the potential for functional recovery in dysfunctional areas following reperfusion， and provide clinicians with valuable information for individualized treatment.